Adding Drives to RAID Setup

Right now, I have two 1TB drives in a RAID 1 (mirrored) setup. Down the road, I can see myself getting another two 1TB drives. If this happens, I imagine I would want a RAID 10 setup. Will it wipe all the data from my existing RAID 1 setup if I try to create the RAID 10 setup with the two new drives?

I don't really have a place to store 1 TB of data while i expand my available space to 2 TB.

If you're talking about making a raid mirror without formatting,
It's even pretty easy to do.

Make sure you have a good backup. We are going to be re-writing the partition map of your disk.
If something were to go wrong you could loose all of your data. That said, this seems to be pretty reliable.

If you want to mirror your boot device you will need to startup off of something else first.
Next open the Terminal and type diskutil list

You'll get an output that looks something like this,

Quote:

[macxmv2:~] admin% diskutil list

/dev/disk0

#: type name size identifier

0: Apple_partition_scheme *172.6 GB disk0

1: Apple_partition_map 31.5 KB disk0s1

2: Apple_Driver43 28.0 KB disk0s2

3: Apple_Driver43 28.0 KB disk0s3

4: Apple_Driver_ATA 28.0 KB disk0s4

5: Apple_Driver_ATA 28.0 KB disk0s5

6: Apple_FWDriver 256.0 KB disk0s6

7: Apple_Driver_IOKit 256.0 KB disk0s7

8: Apple_Patches 256.0 KB disk0s8

9: Apple_HFS Server HD 172.5 GB disk0s9

/dev/disk1

#: type name size identifier

0: Apple_partition_scheme *172.6 GB disk1

1: Apple_partition_map 31.5 KB disk1s1

2: Apple_Driver43 28.0 KB disk1s2

3: Apple_Driver43 28.0 KB disk1s3

4: Apple_Driver_ATA 28.0 KB disk1s4

5: Apple_Driver_ATA 28.0 KB disk1s5

6: Apple_FWDriver 256.0 KB disk1s6

7: Apple_Driver_IOKit 256.0 KB disk1s7

8: Apple_Patches 256.0 KB disk1s8

9: Apple_HFS SecondHD 172.5 GB disk1s9

The main thing we are looking for here is the device name of our disks. Let's pretend we are going to make a mirror of our boot disk, disk0.

We've decided that we want to create a mirror of disk0 so typediskutil enableRAID mirror disk0
and the drive in question will vanish from the desktop, but it will reappear in like 20 sec.

Now that your drive is back you can rebuild the new RAID set with either with a
diskutil repairMirror (RAID device name) (Bad slice) (Good member) (New member)
or just open up Disk Utility, drag and drop, and then watch the pretty progress bar.

If you mirrored your boot device you can startup off of it and get back to work before you rebuild since you can rebuild in the background now.

Note: Mirroring can take a pretty long time... like an hour for 10 GB's!